South Africa's competition commission said Tuesday it had launched investigations into pharmaceutical giants Roche, Pfizer and Aspen for suspected overpricing of cancer drugs.
Swiss firm Roche and US company Pfizer are being probed over "excessive pricing" for breast and lung cancer medications respectively, while South Africa's Aspen is being investigated for overcharging over three different drugs.
"The commission has reason to believe that Roche and its USA-based biotechnology company, Genentech, have and continue to engage in excessive pricing, price discrimination... in the provision of breast cancer medicine in South Africa," it said in a statement.
It said it suspected Roche of engaging in anti-competitive conduct, prolonging its "hold on breast cancer drugs" and preventing cheaper generic alternatives from reaching the market.
Roche is also accused of charging different rates to private and public sector patients, possibly in breach of local competition laws.
The Swiss giant said it had not yet been notified of the investigation.
If notified, "we will be cooperating with the authorities and will provide all required information while responding to the potential allegation," said Roche.
The South African commission said it had "also initiated an investigation against pharmaceutical giant, Pfizer, for suspected excessive pricing of lung cancer medication in South Africa".
The commission is also investigating South Africa's Aspen for overcharging for three drugs used in the treatment of various strains of cancer including leukaemia, myeloma and ovarian cancer.
It suspects Aspen of "abuse of dominance by charging excessive prices in the provision of lifesaving cancer medicines in South Africa".
Aspen denied the allegations saying that pharmaceutical prices in the country are approved by the health ministry which establishes a universal fixed price for each drug.
"Aspen has not increased pricing of its products outside of this regulatory framework and has clearly demonstrated its commitment to providing quality medicines affordably over many years," it said in a statement.
"The supply of the oncology products in question is no exception."
Aspen is already under investigation in the European Union over suspicions that it abused its dominant market position in breach of EU antitrust rules.
The EU probe was announced last month.
Explore further: Roche buying Seragon in US for up to $1.7 billion